This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Neurotransmitter transporters are membrane proteins that utilize the electrochemical gradient of sodium for uphill translocation of their substrate/neurotransmitter from the extracellular region to the cell interior. This process involves a structural transition from outward-facing conformation to inward-facing conformation that enables the cyclical recognition/binding and release of the substrate. The crystal structure of the aspartate transporter GltPh, an archaeal homologue of human glutamate transporters, has been resolved in both conformations. We intend to perform MD runs using these two crystal structures towards gaining insights into molecular mechanisms of interactions that play a driving role in the passage between these two conformers.